/**
 * Copyright (C) 2012 Oleg Anastassov <o.anastasov@gmail.com>
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package kz.kstu.ent.app.util.locator;

import org.apache.log4j.Logger;

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.rmi.PortableRemoteObject;
import java.util.HashMap;
import java.util.Map;

/**
 * @author Oleg Anastassov
 *         created: 26.07.11 21:07
 */
public abstract class AbstractServiceLocator implements ServiceLocator {

    private static final Logger LOGGER = Logger.getLogger(AbstractServiceLocator.class);

    private static Map<String, Object> serviceCache = new HashMap<String, Object>();

    public <T> T getService(String serviceName, Class<T> serviceInterface) {
        String serviceFullName = getServiceFullName(serviceName);
        T service;
        if (serviceCache.containsKey(serviceFullName)) {
            service = (T) serviceCache.get(serviceFullName);
        } else {
            service = createService(serviceFullName, serviceInterface);
        }
        return service;
    }

    protected <T> T createService(String serviceFullName, Class<T> serviceInterface) {
        InitialContext context = getInitialContext();
        T service;
        try {
            service = (T) PortableRemoteObject.narrow(context.lookup(serviceFullName), serviceInterface);
            serviceCache.put(serviceFullName, service);
        } catch (NamingException e) {
            //TODO: replace own exception
            throw new RuntimeException(e);
        }
        return service;
    }

    @Override
    public void closeInitialContext() {
        try {
            InitialContext initialContext = getInitialContext();
            if (initialContext != null) {
                initialContext.close();
                LOGGER.debug("Initial context was closed");
            }
        } catch (NamingException e) {
            LOGGER.error(e.getMessage(), e);
        }
    }

    protected abstract String getServiceFullName(String serviceName);

    protected abstract InitialContext getInitialContext();

}
